Andor sCMOS camera Buffer Problem(slow frame rate)

[Seanshen111]

Hi there,

I am using Andor Zyla 5.5 model controlled by Labview to acquire images in high speed.The labview libraries are provided by Andor.  I used the following settings: Rolling Shutter, 560 MHz readout rate, 2.72e-5 s Exposure time, External Trigger signal (10kHz), Overlap ON, AOI(1024X8 pixels). According to the specs, it should be running at as high as 27,027 fps. But once I set the frame rate higher than 5,000 fps, the acquisition stucked after a while.The real-time display is "frozen" after  continuing display for a while.

Even if I removed anything other than download from the WaitForBuffer.vi, still not working. Then I looked into the acquisition loop, it seems like camera run out of input buffer queue so it has to wait until some buffer space is queued back from output buffer queue. The strange thing is in either circular buffer mode or simple live mode, it always queue back the buffer when it is buffer is not used It seems that something is occupying the time resources so that the loop is too slow hence it cannot catch up? I assigned sufficient buffer with the createBuffer.vi  still no use.

It's just so confusing to me which step actually delays the looping time? I tried using queue instead of local variables but still no luck. 

Apart from the software, I am using USB 3.0 port for data transfer. Is it because of the limitation of the USB port speed or the RAM speed. BTW, my RAM is DDR3-1600 and 8GB size.  

I have attached respective files, I would appreciate any help in camera buffer management or experienced users with Andor cameras. Thank you so much! I appreciate any of your help!

Kind regards,

Sean Shen

[carmen9]

Hi,

Have you seen this manual from Andor? 

And there's this video on circular buffer

Hope it helps.

[Seanshen111]

Hi,

Yes, I've seen this manual and I was using a circular buffer in the acquisition program. But still not working. Actually, I was using the ANDOR LABVIEW sdk downloaded from the Andor service center. They provided many example programs. The one I was using is modified from the example called Circular_buffer.vi. I checked the frame rate(e.g. 6,000 fps) by monitoring the time consumed inside the for loop in the real-time display part. I removed everything that would slow down the loop including the array transformation and only retained the wait-buffer and queue-buffer function. The highest it can reach is 6000 fps. When running at a frame rate lower than 6,000 fps, it's fine. But when set to higher frame rate, the loop would have a delay and the time was not the exact frame time it should be. After a few seconds, the display would freeze and the acquisition seems to stop because full of buffer. My guess is that when set to higher than 6,000 fps, the out-queue is slower than the in-queue so the buffer memory on camera gradually becomes full and forces the camera to stop acquisition.

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I don't know whether the reason for the troubles is the decreased throughput or many collateral processes in Labview. Or any hardware limitations(USB 3.0port or PCI board or RAM speed)?

Regards

Sean Shen

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@carmen9 wrote:

Hi,

Have you seen this manual from Andor? 

And there's this video on circular buffer

Hope it helps.

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